Are there studies which compare the performance of Tagalog and non-Tagalog speakers in Filipino?

Yes, there is at least one. In October 1963, the Burea of Public Schools conducted a study on the relative literacy in "the eight major linguistic regions, namely Bicol, Cebu-Visayan, Hiligaynon, Ilocano, Pampanga sic, Pangasinan, Samar-Leyte, and Tagalog." In the study, "3,830 Grave VI pupils selected at random from twenty-four school divisions representing the eight major linguistic regions were given test sic in both English and Pilipino". The definition of literacy followed that of UNESCO: "A person is considered literate, who can both read with understanding and write a short simple statement on his everyday life." (For simplicity of analysis, the figures for the "semiliterate" and "illiterate" are not considered here.)

The result of the study are as follows:

Literacy.............PILIPINO...ENGLISH
BICOL..................69.06....47.23
1. Camarines Norte.....80.23....37.21
2. Camarines Sur.......64.71....51.13
 
CEBU-VISAYAN...........81.67....76.68
1. Bohol...............71.25....76.25
2. Cebu................75.98....69.61
3. Cotabato II.........88.92....81.04
4. Davao City..........88.51....80.46
5. Misamis Occidental..70.77....67.69
 
HILIGAYNON.............50.00....46.20
1. Aklan...............74.77....57.94
2. Antique.............60.87....58.26
3. Negros Occidental...34.52....35.71
 
ILOCANO................62.36....63.67
1. Abra................43.48....58.70
2. Baguio..............65.22....73.91
3. La Union............57.60....53.60
4. Zambales............76.00....75.00
 
PAMPANGO...............75.00....71.15
1. Pampanga............75.00....71.15
 
PANGASINAN.............53.33....46.66
1. Pangasinan..........53.33....46.66
 
SAMAR-LEYTE............59.21....57.89
1. Southern Leyte......59.21....57.89
 
TAGALOG................88.47....70.31
1. Bulacan.............83.11....55.11
2. Cavite..............93.08....74.62
3. Laguna..............78.15....66.89
4. Manila..............89.19....74.85
5. Marinduque..........97.44....92.31
6. Oriental Mindoro....90.14....74.65
7. Quezon Province.....95.02....73.30
 
T O T A L..............74.25....65.09
 
Notes:
i. Aklan and Antique are placed under "Hiligaynon," even if the majority language in Aklan is Akeanon, and that in Antique is Kinaray-a.
ii. Zambales categorized as "llocano," when the proportion of Ilokano speakers there was 32.5% during the 1960 census, or roughly a third, the rest being mainly Sambal and Tagalog.
iii. The division selected for the study was of Samar-Leyte was Southern Leyte, which is predominantly Cebuano-speaking.

Edwin has this to say about the interpretation of this data:

The inequality is immediately apparent: while differences in literacy in English and the imperial subdialect (known as "Pilipino" at that time) are obvious, indeed, glaring in the Tagalog areas, where there is a clear contrast between a foreign language, English, and the

Tagalog-based Pilipino. They are not so apparent in non-Tagalog areas, where pupils are confronted with two foreign languages. Thus, of the 17 school divisions represented, the difference in literacy rate between the subdialect and English was less than 10% in all but

three of these (Camarines Norte, Camarines Sur and Aklan). On the other hand, it was above (in most cases far above) 10% in all Tagalog provinces except Marinduque, where it stood at 5.13%.

 

A more detailed look will emphasize the disparity. In 10 of the 17 non-Tagalog divisions in the study, the difference in literacy between Pilipino and English was 4% or less, in cases where more were literate in Pilipino (2.67% in Antique, 4% in La Union, 1% in Zambales, 3.85% in Pampanga, 3.08% in Misamis Occidental, and 1.3% in Southern Leyte), or literacy was actually greater in English than in Pilipino (as in Bohol, Abra, Baguio, and Negros Occidental). In

Abra, for instance, the lead of those literate in English over those literate in Filipino was a high 15.22 percentage points.

 

In contrast, the difference in literacy between English and Pilipino in the Tagalog school divisions (in favor of the subdialect, of course) becomes even more pronounced with closer scrutiny. It is 14.34% for Manila, 15.49% for Oriental Mindoro, 18.46% for Cavite, 21.72% for Quezon, and nearly 30 percentage points (actually 28.01%) for Bulacan!

 

The exceptions merit some comment. While Camarines Norte is classified under the "Bicol" linguistic area here, the study was conducted in late 1963, at a time when Tagalog was on its way to replacing Bikol as the majority language (the province was 46.70% Tagalog at the time of the 1960 census). Thus, one would expect comprehension of, and literacy in, Pilipino there to approach that of the Tagalog provinces. As for Camarines Sur, a large part of the province is included within the zone, immediately beyond the Tagalog-Bikol linguistic border, in the Bikol-speaking area, which has long had close to 100% bilingualism in Bikol and Tagalog (not to mention the fact that one Camarines Sur town, Del Gallego, is mainly Tagalog-speaking). If the study had been done in, say, Albay or Catanduanes, the results might have been different, and closer to the non-Tagalog norm. I do not have enough information about Aklan, the third

exception, where literacy in the subdialect compared to English (74.77% against 57.94%) was unusually high. But again, as far as the survey is concerned, this is the exception rather than the rule.

 

In the Tagalog areas, the exception, Marinduque, where the gap between English and Pilipino is only 5.13%, deserves mention. There are many possible explanations. I notice, though, that the proportion of those literate in English there is an exceptionally high 92.31%, far beyond that of any other school division, Tagalog or non-Tagalog (the next highest, Cotabato II, registered 81.04%). I can only attribute this to a relatively high standard of education in

Marinduque [where literacy in English compared very favorably with "cosmopolitan" Manila (in which it was 74.85%)], considering that literacy in Pilipino in that province (97.44%) was also the highest in the Tagalog Region and the entire country.

 

If anything, the results of the study point to the fact that subdialect-medium education is advantageous only in the Tagalog areas, where literacy in a subdialect derived from their native tongue is unquestionably superior to that in English. On the other hand, in view of the small difference in literacy rate between English and "Pilipino" in non-Tagalog areas, despite twenty years or so of compulsory teaching of the latter (the forerunner of the imperial subdialect became a required subject during the Japanese Occupation), constant exposure to the mass media (movies, radio, the print media and later television), and the political and economic dominance of Manila, it would be far more advantageous for pupils in non-Tagalog areas to be taught in English (compared to the subdialect), or better still, in their regional languages.

 

Ironically, this same study was quoted in the book "The Case for Pilipino" by Filipino language apologist Apolinario Parale, but he arrived at a different conclusion: because "the percentage of literacy in Pilipino was 74.25 and that in English, 65.09" (page 66-I), the imperial subdialect should be used as the medium in the entire educational system, replacing the "vernacular" even in the non-Tagalog areas (regional languages were still the medium in the first two grades in public schools at the time of the study).